1. Field of the Invention
The present invention relates to a method for tagging macro-organisms, especially fish, for identification purposes. More particularly, this invention concerns the use of visible implant tags encoded with fluorescent dyes or, more preferably, fluorescent pigments and various methods for reading the code.
2. Description of Related Art
The use of visible implant tags for identifying macro-organisms has been disclosed elsewhere as has the use of fluorescent colorants for identifying macro-organisms. These methods generally require the capture of the macro-organism to be identified and/or the use of sophisticated equipment to locate and read the tag.
U.S. Pat. No. 4,750,490 to Haw et al., the disclosure of which is incorporated herein by reference, discloses the use of visible implant tags for the identification of fish. The tags are implanted into transparent or semi-transparent tissue. Upon capture of the fish, the location of the visible implant tags can be ascertained visually and the tag can be excised and read, or read through the transparent or semitransparent tissue. The visible implant tags may have information encoded thereon as indentations forming binary words, as alpha-numeric codes, or as shapes of visually differentiable colors. This information may be read optically either manually or mechanically.
U.S. Pat. No. 4,392,236 to Sandstram et al. describes an animal identification system utilizing fluorescent implanted tags coded with one or more higher atomic number chemical elements and an automated method for reading the coded information. The tags are read by inserting the animal, a fish, into a specimen holder which is in turn inserted into a machine designed to expose only the tag to x-rays, while masking the rest of the fish, and measuring the fluorescent X-radiation. Alternatively, a variation was contemplated in which a tagged animal could be allowed limited movement in a confined channel and a three-dimensional locating and tracking means could control the application of the X-ray beam to only the tag.